Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A method of transmitting data so as to reduce electromagnetic interference associated therewith, the method comprising: receiving a plurality of un-encoded control symbols and a plurality of data symbols; generating one or more pseudo-random values based on a transmitting linear feedback shift register (LFSR); and scrambling only the plurality of un-encoded control symbols, the plurality of un-encoded control symbols being scrambled with the generated one or more pseudo-random values in order to produce a plurality of corresponding pseudo-random values, where a plurality of scrambled corresponding control symbols are retrieved from a lookup table based on the plurality of corresponding pseudo-random values generated using the scrambling; wherein: transmitting of the plurality of scrambled corresponding control symbols minimizes undesirable electromagnetic radiation and interference; the receiving LFSR comprises a self-synchronizing LFSR; and the receiving LFSR is forced to a known value to self-synchronize, the known value comprising a channel number selected from a plurality of channel numbers.
A method to reduce electromagnetic interference (EMI) during data transmission scrambles control symbols associated with an HDMI interface using pseudo-random numbers. The method involves receiving un-encoded control symbols and data symbols. A transmitting linear feedback shift register (LFSR) generates pseudo-random values used to scramble *only* the un-encoded control symbols. The scrambled control symbols are retrieved from a lookup table. Transmitting these scrambled control symbols minimizes EMI. The receiving end uses a self-synchronizing LFSR that synchronizes to a known value based on a channel number.
2. The method of transmitting data of claim 1 , wherein the plurality of un-encoded control symbols is associated with a High-Definition Multimedia Interface (HDMI) interface.
The method of reducing electromagnetic interference (EMI) during data transmission as described above, specifically applies to systems using a High-Definition Multimedia Interface (HDMI) interface for transmitting the control and data symbols. The control symbols associated with HDMI are scrambled using pseudo-random numbers derived from a transmitting linear feedback shift register (LFSR), to reduce EMI when transmitted.
3. The method of claim 1 , further comprising using a sub-set of bits generated by the transmitting LFSR, the sub-set of bits being used to generate the one or more pseudo-random values.
In the method of reducing electromagnetic interference (EMI) by scrambling control symbols with pseudo-random values, a subset of bits generated by the transmitting linear feedback shift register (LFSR) is used to generate the pseudo-random values. The entire output of the LFSR is not used; rather, a selection of bits from the LFSR output is extracted and used as the source for the pseudo-random scrambling process.
4. The method of claim 3 , wherein the using of the sub-set of bits comprises using a set of least significant bits to generate the plurality of pseudo-random values.
In the method where a subset of bits from the transmitting linear feedback shift register (LFSR) are used to generate pseudo-random values, the subset of bits comprises the *least* significant bits (LSBs) of the LFSR output. The least significant bits of the LFSR output are extracted and used to generate the pseudo-random values that scramble the control symbols.
5. The method of claim 3 , wherein the using of the sub-set of bits comprises using a set of most significant bits to generate the plurality of pseudo-random values.
In the method where a subset of bits from the transmitting linear feedback shift register (LFSR) are used to generate pseudo-random values, the subset of bits comprises the *most* significant bits (MSBs) of the LFSR output. The most significant bits of the LFSR output are extracted and used to generate the pseudo-random values that scramble the control symbols.
6. The method of claim 1 , wherein the transmitting of the plurality of scrambled corresponding control symbols further comprises transmitting the plurality of scrambled corresponding control symbols when the transmitting LFSR and the receiving LFSR are synchronized.
In the method of reducing electromagnetic interference (EMI) by scrambling control symbols, transmitting the scrambled control symbols only occurs when the transmitting linear feedback shift register (LFSR) and the receiving LFSR are synchronized. Scrambled symbols are not transmitted unless synchronization has been achieved between the transmitting and receiving LFSRs.
7. The method of claim 1 , further comprising updating a running disparity count after each one of the plurality of scrambled corresponding control symbols is transmitted.
The method of reducing electromagnetic interference (EMI) by scrambling control symbols includes updating a running disparity count after each scrambled control symbol is transmitted. This involves maintaining a balance between positive and negative signal levels and adjusting the transmitted symbols to maintain this balance by incrementing or decrementing the disparity count after each symbol transmission.
8. The method of claim 7 , further comprising using the running disparity count for the retrieving of the plurality of scrambled corresponding control symbols.
In the method that updates a running disparity count after each scrambled control symbol transmission, the running disparity count is then used to retrieve the correct scrambled control symbols from the lookup table. The disparity count influences which scrambled symbol is selected from the lookup table, likely to maintain DC balance and reduce EMI.
9. The method of claim 1 , further comprising padding the generated one or more pseudo-random values with one or more additional bits.
In the method of reducing electromagnetic interference (EMI) by scrambling control symbols, after the one or more pseudo-random values are generated, they are padded with one or more additional bits. Additional bits are appended to the generated pseudo-random values before they are used as an index or input to the lookup table.
10. The method of claim 9 , further comprising generating an index value for use with the lookup table by exclusive OR′ing the padded one or more pseudo-random values with the generated one or more pseudo-random values.
This invention relates to cryptographic systems, specifically methods for generating and using lookup tables to enhance security in data processing. The problem addressed is the need for efficient and secure methods to generate and utilize pseudo-random values in cryptographic operations, particularly where lookup tables are employed to improve performance or security. The method involves generating one or more pseudo-random values using a cryptographic algorithm. These values are then padded to a predetermined length, ensuring consistency for subsequent operations. The padded values are combined with additional pseudo-random values, also generated cryptographically, through an exclusive OR (XOR) operation. This combination produces an index value, which is then used to access a lookup table. The lookup table contains precomputed values or operations that facilitate faster or more secure processing of data, such as encryption, decryption, or authentication. The use of XOR in this context ensures that the index value is derived in a manner that maintains cryptographic strength, preventing predictable patterns that could be exploited by attackers. The lookup table may contain values derived from cryptographic functions, such as substitution boxes (S-boxes) or other precomputed transformations, allowing for efficient execution of cryptographic operations. This approach balances performance and security, making it suitable for applications requiring both speed and robustness.
11. An apparatus, the apparatus comprising: a transmitting linear feedback shift register (LFSR); and an electronic circuit configured to: receive a plurality of un-encoded control symbols and a plurality of data symbols; generate one or more pseudo-random values based on the transmitting LFSR; and scramble only the plurality of un-encoded control symbols, the plurality of un-encoded control symbols being scrambled with the generated one or more pseudo-random values in order to produce a plurality of corresponding pseudo-random values, where a plurality of scrambled corresponding control symbols are retrieved from a lookup table based on the plurality of corresponding pseudo-random values generated using the scrambling; wherein: transmission of the plurality of scrambled corresponding control symbols minimizes undesirable electromagnetic radiation and interference; the receiving LFSR comprises a self-synchronizing LFSR; and the receiving LFSR is forced to a known value to self-synchronize, the known value comprising a channel number selected from a plurality of channel numbers.
An apparatus that reduces electromagnetic interference (EMI) during data transmission includes a transmitting linear feedback shift register (LFSR) and electronic circuitry. The circuit receives un-encoded control and data symbols. The LFSR generates pseudo-random values used to scramble *only* the un-encoded control symbols. The scrambled control symbols are retrieved from a lookup table. Transmitting these scrambled control symbols minimizes EMI. The receiving end uses a self-synchronizing LFSR that synchronizes to a known value based on a channel number.
12. The apparatus of claim 11 , wherein the plurality of un-encoded control symbols are associated with a High-Definition Multimedia Interface (HDMI) interface.
The apparatus for reducing electromagnetic interference (EMI) during data transmission, specifically applies to systems using a High-Definition Multimedia Interface (HDMI) interface for transmitting the control and data symbols. The control symbols associated with HDMI are scrambled using pseudo-random numbers derived from a transmitting linear feedback shift register (LFSR), to reduce EMI when transmitted.
13. The apparatus of claim 12 , wherein the electronic circuit is further configured to use a sub-set of bits generated by the transmitting LFSR, the sub-set of bits being used to generate the one or more pseudo-random values.
In the apparatus for reducing EMI, the electronic circuit is configured to use a subset of bits generated by the transmitting linear feedback shift register (LFSR) to generate the pseudo-random values. The entire output of the LFSR is not used; rather, a selection of bits from the LFSR output is extracted and used as the source for the pseudo-random scrambling process.
14. The apparatus of claim 13 , wherein the use of the sub-set of bits further comprises use of a set of least significant bits to generate the plurality of pseudo-random values.
In the apparatus where a subset of bits from the transmitting linear feedback shift register (LFSR) are used to generate pseudo-random values, the subset of bits comprises the *least* significant bits (LSBs) of the LFSR output. The electronic circuit is configured to extract and use the least significant bits to generate the pseudo-random values that scramble the control symbols.
15. The apparatus of claim 13 , wherein the use of the sub-set of bits further comprises use of a set of most significant bits to generate the plurality of pseudo-random values.
In the apparatus where a subset of bits from the transmitting linear feedback shift register (LFSR) are used to generate pseudo-random values, the subset of bits comprises the *most* significant bits (MSBs) of the LFSR output. The electronic circuit is configured to extract and use the most significant bits to generate the pseudo-random values that scramble the control symbols.
16. The apparatus of claim 11 , wherein the transmission of the plurality of scrambled corresponding control symbols further comprises transmission of the plurality of scrambled corresponding control symbols when the transmitting LFSR and the receiving LFSR are synchronized.
This invention relates to secure communication systems, specifically apparatuses for transmitting and receiving scrambled control symbols using synchronized linear feedback shift registers (LFSRs). The problem addressed is ensuring secure and reliable transmission of control symbols in communication systems where synchronization between transmitting and receiving LFSRs is critical for proper descrambling. The apparatus includes a transmitting LFSR and a receiving LFSR, each configured to generate a pseudorandom sequence for scrambling and descrambling control symbols. The transmitting LFSR scrambles a plurality of control symbols using its generated sequence, and the receiving LFSR descrambles the received symbols using its synchronized sequence. The transmission of scrambled control symbols occurs only when the transmitting and receiving LFSRs are synchronized, ensuring that the descrambling process is accurate and the control symbols are correctly recovered. Synchronization may be achieved through initialization sequences, periodic resynchronization, or other synchronization mechanisms. The apparatus may also include error detection and correction mechanisms to handle transmission errors that could disrupt synchronization. This ensures robust and secure communication of control symbols in environments where synchronization integrity is essential.
17. The apparatus of claim 11 , wherein the electronic circuit is further configured to update a running disparity count after each one of the plurality of scrambled corresponding control symbols is transmitted.
The apparatus for reducing electromagnetic interference (EMI) by scrambling control symbols is further configured to update a running disparity count after each scrambled control symbol is transmitted. The electronic circuit is responsible for maintaining a balance between positive and negative signal levels and adjusting the transmitted symbols to maintain this balance by incrementing or decrementing the disparity count after each symbol transmission.
18. The apparatus of claim 17 , wherein the running disparity count is utilized for the retrieval of the plurality of scrambled corresponding control symbols.
In the apparatus that updates a running disparity count after each scrambled control symbol transmission, the running disparity count is then used by the electronic circuit to retrieve the correct scrambled control symbols from the lookup table. The disparity count influences which scrambled symbol is selected from the lookup table, likely to maintain DC balance and reduce EMI.
19. The apparatus of claim 11 , wherein the electronic circuit is further configured to pad the generated one or more pseudo-random values with one or more additional bits.
In the apparatus for reducing electromagnetic interference (EMI) by scrambling control symbols, the electronic circuit is configured to pad the generated pseudo-random values with one or more additional bits. Additional bits are appended to the generated pseudo-random values before they are used as an index or input to the lookup table.
20. The apparatus of claim 19 , wherein the electronic circuit is further configured to generate an index value for use with the lookup table via an exclusive OR operation of the padded one or more pseudo-random values with the generated one or more pseudo-random values.
In the apparatus where the generated pseudo-random values are padded with additional bits, the electronic circuit is further configured to create an index value for the lookup table by performing an exclusive OR (XOR) operation between the original, unpadded pseudo-random values and the padded pseudo-random values. This XOR operation generates the final index used to access the scrambled control symbol in the lookup table.
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December 5, 2017
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